Who's the daddy?

I have known for some time that my sister's biological father cannot be the man who brought us both up. She has no idea this might be the case. Should I tell her the truth and risk losing her trust - or take my secret with me to the grave?

I am in my 50s and have a younger sister. Both of us are happily married. A couple of years ago, I discovered that we must have different biological fathers as a result of a conversation about blood donation, when I realised that her blood type precluded the possibility of her being my father's natural child. I know for certain this is the case, as I used to work for the transfusion department of our local hospital and have known my parents' blood types for many years. Nevertheless, I have kept this information to myself.

My father has been dead for more than 30 years and my mother, who is in her late 70s, is a difficult, angry person. I don't believe she would tell my sister who her biological father is and would probably deny the possibility that it was anyone other than her husband.

My sister says she never really knew "our" dad but I always put that down to the fact that he died when she was a child and that she was frightened of his violent temper. He never hit her, only me, but he did terrify her.

Should I tell her what I have learned? My instinct is to avoid a family row and to avoid unsettling her without being able to provide her with any answers. However, am I taking the protective-elder-sister role to far? We love and care for each other very much and I would hate to upset her needlessly, but I do hate keeping such an important secret from her - although it is actually my mother's secret, not mine.

She may welcome this news

As a younger sister myself, I can imagine how infuriated I would feel if my elder sister were to withhold such important information from me, even if she thought she was acting in my best interests. Explain what you have discovered about the blood types and let her draw her own conclusions. That way you will not be "telling" her, but helping her to grasp the truth. If she was terrified by the person she thinks of as her father, there is every chance she may actually welcome this news. In the event that your mother refuses to reveal the biological father's identity, then your sister may have to learn to live with a question that cannot be answered - but life poses many such questions. Who is to say that this need have a negative effect on her life? As long as she is reassured that her relationship with you remains absolutely unchanged she may well find the strength to come to terms with this revelation.

BN, London

I kept it a secret

I discovered a similar secret myself a few years back; my sister had suspected that we had different fathers and I didn't really think much of it. The thought seemed to bother her, though, and we arranged to be tested. The results came straight to me and confirmed that we did indeed have different fathers, but I let my sister believe the contrary.

Our mother had recently died, so my sister had no obvious way of finding out the truth; I kept what I had learned from my sister because it would have simply raised unanswerable questions. My mother and father weren't the greatest of parents but they were there for us as we grew up and I felt that to disrupt this belief in us as a family would have caused more harm than good. I often feel guilty for keeping such a secret but I love my sister and wanted to protect her from any hurt or upset the truth would inevitably bring.

If my mum were alive I might feel differently but that is more because I am angry at the way she behaved in her lifetime towards us. It has been frustrating to be able to prove that my mother was a hypocrite only after she died. Is it possible you have similar feelings towards your mother? If so, it is unlikely that your desire to reveal everything to your sister is to do with her sense of identity; it's more probably to do with wanting vengeance on a bad mother.

Name and address withheld

Find out who the father is first

When we were growing up, my siblings and I found our father terrifying, violent and completely detached from us. Now, in our 40s, we have discovered too late the secret that was plaguing him and denying him the opportunity to create meaningful relationships with his family. We found out that our father was the natural son of our great-uncle - his mother's brother-in-law. Apparently, when growing up, he was simply left out of family life and made to feel like a spare part, a constant reminder of a humiliating liaison between my grandmother and her brother-in-law.

My father only found out about his parentage when his uncle died, and the secret was revealed in his will, by which time all the other parties had predeceased him. I remember the period that coincided with my great-uncle's death, and the total breakdown that scarred my family for ever, to the point where we all decided never to speak to our father again. None of us knew what had possessed him, but looking back now, my guess is that it was a combination of identity confusion, anger and shame. He would wait another 20 years before telling anyone. My great-uncle may have been my father's "real" father but I cannot recall any trace of delight when he met me, his grandson, for the first time - there was only cold indifference.

Because of this, I would urge you to find out from your mother who the biological father is before sharing this secret with your sister. It could well be someone you have known all your lives, or someone about whom your feelings are quite ambiguous.

Name and address withheld

Openness isn't always the way

It is very fashionable now to confess all; to bring everything out in the open. But in what way does this benefit anyone? If you reveal your mother's secret, you won't just be destroying your sister's sense of who she is. It sounds as if you have a close family - do you really want to disrupt it? It seems terribly old-fashioned to carry secrets such as this to the grave but modern openness isn't always the best way forward.

SL, via email

Don't jump to conclusions

There are several imponderables here, and without knowing the specific blood groups that you refer to, it is difficult to look at all the possibilities. However, as a doctor and research scientist, I would point out that mutations can occur spontaneously in eggs or sperm that alter blood-group inheritance, so that a genuine biological child appears to be an impossibility based on their blood group alone. Of course, you may be correct, but since doubt exists and there is now no way to know for certain, why create a lot of hurt and unrest?

SD, Welwyn, Herts

Time may not be a healer

In my experience, "explosive" family secrets, especially regarding one's parentage, prove even more incendiary with the passing of time. While such revelations are painful and potentially disruptive of family relationships, when the truth is ultimately known, it can be even more painful to learn that one has been kept in the dark for so long by well-meaning, but horribly misguided relations.

TP, Montana, US

Your sister has a right to know

Your mother has kept this secret for a reason - what has made her so "difficult and angry"? Why was your father violent and why did he hit only you? Where was your sister's "real" father when your mother was left widowed ?

I think your sister has a right to know what you've found out, so that she has a chance to ask your mother about her "real" father, while she is still around. She may find it hard to forgive you if you don't give her this opportunity.

CR, via email

What the expert thinks - Linda Blair

It may help if we turn this problem on its head. Let us suppose your father is not actually your biological father. Would you want to know this? I suspect you would. But would you want your sister to know before you did? That is less likely. And how would you feel if she had known for some time, but only decided to tell you now?

You need to think carefully about what you would hope to achieve by telling your sister what you know. I take it she is not aware of any such possibility. If you disclose this knowledge, it will raise a number of questions in her mind. These will have little chance of being answered because the man she thought was her father is long dead, and from what you say about your mother, it is unlikely that your sister would learn anything from her. You would probably just upset her.

There are, however, two circumstances when it would be advisable to tell her what you know. The first is if she or any of her children are diagnosed with a medical condition that could be improved or averted if she knew more about her genetic inheritance. Under those conditions you should also encourage your mother to tell what she knows - and surely, to safeguard the health of her child or her grandchildren, she would do so.

The second situation would be if your sister asks you about this issue. Whenever we are asked a direct question, it is always best in the long term to tell the truth, even if that makes things awkward in the short term. Anyway, if she does ask you about who her father is, at least that would indicate that she already has suspicions, so she will be more prepared for your answer than she is now.

In general, if ever you do decide to tell someone something about themselves that they don't know, the best time to do so is as soon as you become aware of that information. That way the person concerned is able to "own" the knowledge at the earliest possible moment. In your case, however, that moment has long gone.

You need to ask yourself why you're feeling this way now, after so long. Is it because the knowledge is weighing ever more heavily on you? If that is the case, why not write everything you know in a letter to your sister? But rather than sending the note, destroy it. That way you'll have "offloaded", but no one will be distressed as a result.

Ask yourself if your desire to divulge your secret is less about your sister and really more about your relationship with your mother. You speak of your mother in negative terms. If you tell your sister what you know, you would be stealing a march on your mother and allowing yourself to feel more powerful in relation to her. If this explanation hits home, I advise you to seek help to work through your feelings towards your mother. That way you can let go of your anger towards her and feel easier in her presence before it's too late.

Next week

Am I truly compatible with my partner?

I'm 35 and in a situation where everything seems tangled up. I'm leaving a stressful job at the end of the summer and intend to leave the shared rented house I'm living in and finally get a place of my own - or move in with my partner, who lives in another city.

She is wonderful: loving, intelligent, and generous. But we have very different interests - I love culture, travel and intellectual discussion (I have recently completed a PhD) and I don't want kids. She didn't finish university, lets me plan all our outings, loves children and likes to watch television every night. I suspect our relationship has worked for the past year because we only see each other at weekends, have a great deal of mutual respect, and work hard to communicate with one another. Now I'm in a position where I can move in with her and see how it goes. (If I decide to to do this, I will try to find a job where she lives.) I'd rather move to another city we both like but she wouldn't be able to come with me immediately, although she would like to follow at some point.

Alternatively, I could break up with her and do my own thing. I never truly fell in love with her, although she is unaware of this, but I do love her. She is very much in love with me and wants me to have counselling to safeguard our relationship. I have had therapy in the past because I am extremely stressed, and recently had a serious health scare related to this. But I'm still confused as to what is right for me.

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